The present invention relates to an apparatus for cleaning copier rollers, and in particular, a retrofit assembly designed for cleaning the fuser and pressure rollers within certain copiers that did not include cleaning rollers at the time of manufacture.
Toner-based photocopier machines, a typical example of which is shown in FIG. 1, contain a plurality of rollers to apply and fix toner dust to the surface of paper. In order to reproduce an original document image onto a second reproduction document, toner is transferred electrostatically and fused onto the second document within a fuser apparatus. This fusion process and the corresponding drawbacks are the central focus of the cleaning apparatus of the present invention.
Toner is baked or fused onto a second reproduction document in a series of steps. First, the reproduction document is fed generally in between two rollers which apply an oppositional force upon the paper. These two rollers consist of a pressure roller and a fuser roller. The pressure roller serves to feed the paper through the toner apparatus while continuously applying pressure upon the paper which keeps a portion of the paper in firm contact with the fuser roller during the feeding and fusion process. Second, the fuser roller contains an internal fuser lamp which provides a specific level of heat to the outer surface of the fuser roller. This fuser roller surface heat in turn is applied to the toner dust on the surface of the paper as the paper is brought into direct contact with the fuser roller. As the reproduction document is fed through the fuser apparatus, the once loose toner dust is fused onto the surface of the reproduction document.
This fusion process invariably causes excess toner dust to be left behind on the surface of both the pressure and fuser rollers. This residual toner dust diminishes the life of the fuser apparatus and affects the integrity of the reproductions. A build-up of excess toner dust on the rollers is particularly problematic in that it will tend to create a surface that further attracts and causes more dust build-up with each use of the fuser apparatus. This cyclical build-up problem reduces the useful life of the fuser apparatus, decreases the quality of the reproductions, and poses harm to any adjacent mechanical or electrical components.
Attempts have been made to address some of the mentioned problems. One common approach seeks to prevent initial build-up by modification of the roller surfaces themselves. Another approach focuses on the addition of one or more cleaning rollers to the fuser apparatus.
Modifications to the surface of both the fuser and pressure rollers are designed to minimize initial toner build-up. Generally, a thin layer of material such as polytetrafloroethene (PTFE) is bonded or coated to the outer cylindrical surface of the fuser or pressure rollers. While a PTFE coated surface is partially effective in reducing the adhesion of toner dust on the surface of the rollers, such a coating fails to completely eliminate the build-up of toner dust.
U.S. Pat. Nos. 5,142,122 and 6,078,779 are examples of disclosures that, at least in part, implement additional cleaning rollers that serve to remove impurities, such as excess toner dust, from the surface of the fuser roller. A cleaning roller is placed in contact with the surface of the fuser roller. The cleaning roller is generally made of felt or other fibrous materials. As the cleaning roller and fuser roller come into rotational contact with one another, the fibrous surface of the cleaning roller removes impurities such as toner dust from the surface of the fuser roller.
The art related to such cleaning rollers is limited, however, in that it discloses only cleaning roller apparatuses that are introduced into the fuser apparatus at the time of manufacture. These cleaning rollers are component structures within the manufactured fuser apparatus and are not capable of post-manufacture retrofit installation. Many photocopiers, however, utilize fuser apparatus that do not include such a cleaning roller at the time of manufacture. As a result, many copier users are unable to take advantage of the benefits such a cleaning roller system provides with regard to reproduction quality and fuser apparatus replacement costs. Consequently, there exists a substantial need for some type of retrofit cleaning roller apparatus that can be easily installed or dropped into an existing photocopier that does not have such an assembly already installed.
The preferred embodiment of the present invention provides a retrofit assembly enabling the installation or insertion of a cleaning roller assembly in those fuser apparatus which lack a cleaning roller assembly at the time of manufacture. This retrofitting is made possible by utilizing the existing structure and space available within the housing of presently manufactured fuser apparatus. By permitting the installation of cleaning roller assemblies, many advantages are realized.
Accordingly, the present invention may be characterized as a roller cleaning apparatus for retrofit installation in a photocopier fuser assembly having a housing and a fuser roller mounted in the housing. The apparatus may comprise a mounting strip adapted to engage a surface within the housing, a pair of resilient brackets spaced apart on the mounting strip, and a cleaning roller. Each of the resilient brackets has a bearing portion, and the cleaning roller disposed between the pair of resilient brackets. The cleaning roller has a pair of opposing ends, each rotationally mounted in one of the bearing portions. The resilient brackets are configured so as to bias the cleaning roller against the fuser roller when the mounting strip is engaged with the housing.
One object of the preferred embodiment is to permit the cleaning of fuser rollers so that the life span of fuser apparatus is greatly extended. This life span extension results in cost benefits since frequent replacement costs are significantly reduced. In addition, maintenance costs associated with frequent manual cleaning of the rollers are reduced since the installation of cleaning rollers greatly reduces the need for manual maintenance cleanings.
Another object of the preferred embodiment is to substantially increase the quality of reproductions produced by the copier as a direct result of the removal of impurities from the surface of the fuser and pressure rollers.
Yet another object of the preferred embodiment is to lengthen the life span of adjacent mechanical or electrical components by minimizing their exposure to impurities such as toner dust.
Additional objects, advantages, and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.